Controllable bio-synthetic polymeric hydrogels made from fibrinogen-poly(ethylene glycol) adducts have been successfully employed in tissue engineering. The structural consequences of PEG conjugation to fibrinogen (i.e., PEGylation) in such a hydrogel network are not fully understood. The current investigation details the structural alterations caused to the reduced fibrinogen polypeptides by the covalent attachment of linear or branched PEG chains. The structure of PEGylated fibrinogen polypeptides were comprehensively characterized using small angle X-ray scattering, light scattering, and cryo-transmission electron microscopy. These characterizations concur that the bio-synthetic hybrids self-assemble into elongated objects, having a protein core of about 50 Å in diameter decorated with multiple PEG chains. Conjugates with branched PEG chains were shorter, and have lower average molecular weight compared to conjugates with linear chains. The diameter of the protein core of both samples was similar, suggesting a tail-to-head aggregation of the PEGylated fibrinogen polypeptide. A more complete understanding of this unique structural arrangement can provide further insight into the full extent of biofunctional accessibility in a biomaterial that combines the advantages of synthetic polymers with bioactive proteins.
|Number of pages||8|
|Journal||Journal of Materials Science: Materials in Medicine|
|State||Published - Jan 2010|
Bibliographical noteFunding Information:
Acknowledgment The authors wish to thank Dr. Richard Heenan and Dr. Stephen King at ISIS facility of the Rutherford Appleton Laboratory (RAL, Chilton, UK) for their help with data collection and Dr. Daniel Dikovsky for his support with sample preparation. This research project has been supported by the European Commission under the Framework Program through the Key Action: Strengthening the European Research Area, Research Infrastructures. Contract no: RII3-CT-2003-505925. The authors gratefully acknowledge the financial support of the Israel Science Foundation (grant no. 1140/04).